Katsuhiko Tsuno
Toshiba
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Featured researches published by Katsuhiko Tsuno.
Proceedings of SPIE | 2005
Shoko Suyama; Yoshiyasu Itoh; Katsuhiko Tsuno; Kazuhiko Ohno
Silicon carbide (SiC) is the most advantageous as the material of various telescope mirrors, because of high stiffness, low density, low coefficient of thermal expansion, high thermal conductivity and thermal stability. Newly developed high-strength reaction-sintered silicon carbide (NTSIC), which has two times higher strength than sintered SiC, is one of the most promising candidates for lightweight optical mirror substrate, because of fully dense, lightweight, small sintering shrinkage (±1 %), good shape capability and low processing temperature. In this study, 650mm in diameter mirror substrate of NTSIC was developed for space telescope applications. Three developed points describe below. The first point was to realize the lightweight to thin the thickness of green bodies. Ribs down to 3mm thickness can be obtained by strengthen the green body. The second point was to enlarge the mirror size. 650mm in diameter of mirror substrate can be fabricated with enlarging the diameter in order. The final point was to realize the homogeneity of mirror substrate. Some properties, such as density, bending strength, coefficient of thermal expansion, Youngs modulus, Poissons ratio, fracture toughness, were measured by the test pieces cutting from the fabricated mirror substrates.
Fourth International Asia-Pacific Environmental Remote Sensing Symposium 2004: Remote Sensing of the Atmosphere, Ocean, Environment, and Space | 2005
Katsuhiko Tsuno; Hiroshi Irikado; Kazuhiko Oono; Juro Ishida; Shoko Suyama; Yoshiyasu Itoh; Noboru Ebizuka; Hiroaki Eto; Yutang Dai; Wimin Lin; Toru Suzuki; Hitoshi Omori; Yukari Y. Yui; Toshiyoshi Kimura; Yoshio Tange
Newly developed high-strength reaction-sintered silicon carbide, called New-Technology Silicon Carbide (NT-SiC) is an attractive material for lightweight optical mirror with two times higher bending strength than other SiC materials. The material has advantages in its fabrication process. The sintering temperature is significantly lower than that of pure silicon carbide ceramics and its sintering shrinkage is smaller than one percent. These advantages will provide rapid progress to fabricate large structures. The characteristics of the material are also investigated. The polish of the test piece demonstrated that the polished surface has no pore and is suited to visible region as well as infrared without CVD SiC coating. It is concluded that NT-SiC has potential to provide large lightweight optical mirror.
International Conference on Space Optics — ICSO 2004 | 2017
Juro Ishida; Shoko Suyama; Yoshiyasu Itoh; Noboru Ebizuka; Yutang Dai; Katsuhiko Tsuno; Hiroshi Irikado; Kazuo Hamada; Ohno Kazuhiko; Hiroaki Eto
Newly developed high-strength reaction-sintered silicon carbide is an attractive material for lightweight optical mirror with two times higher bending strength than other SiC materials. The polished surface has no pore and is suited to visible region as well as infrared without CVD SiC coating. The fabrication process, with low temperature and small shrinkage, is also suited to develop large scale objects.
International Conference on Space Optics 2006 | 2017
Katsuhiko Tsuno; Yoshihiko Katsuyama; Eisuke Okumura; Takahide Mizuno; Tatsukaki Hashimoto; Michio Nakayama; Hiroshi Yuasa
HAYABUSA, launched May 2003, is the first Japanese spacecraft to explore the small asteroid Itokawa. HAYABUSA had rendezvous Itokawa in three month in 2005 and touched down it twice to sample the material from it. LIDAR is a one of important navigation sensor to measure the distance between HAYABUSA and Itokawa from 50km to 50m. LIDAR operated in the three months and was estimated to have shot more than 4 million laser pulses and had supplied the ranging data to spacecraft navigation system to approach Itokawa down to 30 m.
International Conference on Space Optics — ICSO 2006 | 2017
Katsuhiko Tsuno; Hiroshi Irikado; Kazuhiko Ono; Shoko Suyama; Yoshiyasu Itoh
New Technology Silicon Carbide (NTSIC®) is a reaction sintered silicon carbide with very high bending strength. Two times higher bending strength than other SiC materials is important characteristics in an optical mirror for space application. The space optics is to endure the launch environment such as mechanical vibration and shock as well as lightweight and good thermal stability of their figure. NTSIC has no open pore. It provides good surface roughness for infrared and visible application, when its surface is polished without additional coatings. Additional advantages are in the fabrication process. The sintering temperature is significantly lower than that of a sintered silicon carbide ceramics and its sintering shrinkage is less than one percent. These advantages will provide rapid progress to fabricate large structures and will enable that one meter mirror will put practical use. The fabrication capability has developed from 250mm to about one meter in these two years, after previous report of NTSIC. It is concluded that NTSIC has potential to provide large lightweight optical mirror.
Proceedings of SPIE | 2007
Katsuhiko Tsuno; Kazuhiko Oono; Hiroshi Irikado; Shoko Suyama; Yoshiyasu Itoh
New-Technology Silicon Carbide (NTSIC(R)) is a reaction sintered silicon carbide with very high bending strength. Two times higher bending strength than other SiC materials is important characteristics in an optical mirror for space application. The space optics is to endure the launch environment such as mechanical vibration and shock as well as lightweight and good thermal stability of their figure. NTSIC has no open pore. It provides good surface roughness for infrared and visible application, when its surface is polished without additional coatings. Additional advantages are in the fabrication process. The sintering temperature is significantly lower than that of a sintered silicon carbide ceramics and its sintering shrinkage is less than one percent. These advantages will provide rapid progress to fabricate large structures. Both reaction bonding method and brazing are studied in order to larger application for larger telescope. It is concluded that NTSIC has potential to provide large lightweight optical mirror.
Proceedings of SPIE | 2005
Katsuhiko Tsuno; Kazuhiko Oono; Hiroshi Irikado; Tomohiro Ueda; Shoko Suyama; Yoshiyasu Itoh
New-Technology Silicon Carbide (NT-SiC) is a reaction sintered silicon carbide with very high bending strength. Two times higher bending strength than other SiC materials is important characteristics in an optical mirror for space application. The space optics is to endure the launch environment such as mechanical vibration and shock as well as lightweight and good thermal stability of their figure. NT-SiC has no open pore. It provides good surface roughness for infrared and visible application, when its surface is polished without additional coatings. Additional advantages are in the fabrication process. The sintering temperature is significantly lower than that of pure silicon carbide ceramics and its sintering shrinkage is smaller than one percent. These advantages will provide rapid progress to fabricate large structures and will enable that one meter mirror will put practical use. It is concluded that NT-SiC has potential to provide large lightweight optical mirror.
Archive | 1988
Katsuhiko Tsuno
The Astrophysical Journal | 1983
一夫 牧島; 和久 満田; 一 井上; 勝二 小山; 勝 松岡; 敏夫 村上; 稔 小田; 嘉明 小川原; 隆哉 大橋; 徳明 柴崎; 靖郎 田中; F. J. Marshall; 幸男 早川; 秀世 國枝; 文命 槙野; 文昭 長瀬; 譲 田原; 重徳 宮本; 博 常深; 克彦 津野; 広順 山下; 一郎 近藤; Kazuo Makishima; Kazuhisa Mitsuda; Hajime Inoue; Katsuji Koyama; Masaru Matsuoka; Toshio Murakami; M. Oda; Yoshiaki Ogawara
Archive | 1988
Katsuhiko Tsuno; Yoshihiko Kameda; Satoshi Akabane